1. Field of the Invention
This invention relates generally to exhaust systems. More particularly, the invention relates to an exhaust header for an internal combustion engine.
2. Description of the Related Art
Within the exhaust system of an engine, gaskets are used to seal the interfaces between the connecting flanges of exhaust pipes, or between an exhaust header flange or other exhaust manifold and the cylinder head. In basic construction, these gaskets are conventionally formed from a sheet consisting of one or more layers of material. A plurality of apertures are formed in the sheet for registration with the passageways of the exhaust pipes or cylinder head and manifold. Bolts or other fasteners typically are employed to develop compressive forces within the interface for securing the assembly into an air tight joint.
Gaskets located between the header flange and the cylinder head may further include metallic material such as copper, steel, aluminum, or the like. Such a combination of a soft material along with a metallic material provides additional rigidity to the gasket. However, such conventional gaskets over time and under repeated thermal cyclings, may have a tendency to develop a compression set which, in turn, may result in a loss of torque within the fasteners and a loosening of the joint. Moreover, as no positive means typically is provided to limit or otherwise control the compression of the gasket, the gaskets may be overcompressed during an installation or maintenance which again leads to the development of a compression set within the gasket.